I want chemical balanced equation

C5H12 + O2 ---> CO2 + H2O

There are five carbons on the left but only one on the right, and on each side the carbon is in a single chemical species. Put a 5 in front of the CO2 on the right hand side.

C5H12 + O2 ---> 5CO2 + H2O

There are twelve hydrogens on the left but only two on the right hand side, and hydrogen is in a single species on each side. Put a 6 in front of the H2O on the right hand side.

C5H12 + O2 ---> 5CO2 + 6H2O

Finally, there are only two oxygens on the left hand side but 16 of them on the right hand side. So put a 8 in front of the O2 on the left hand side.

C5H12 + 8O2 ---> 5CO2 + 6H2O

It's now a balanced chemical equation.

Hopefully this helped! :D

-LavenderVye